One of the most widely advocated strategies for dealing with HIV/AIDS could double the number of multi-drug-resistant HIV cases in the population of men who have sex with men (MSM) in LA County over the next 10 years, cautions a new study.

In the United States, LA County has the largest incident population of HIV positive individuals.

The so-called "test and treat" policy -- which calls for universal testing for HIV as well as treatment with antiretroviral drugs for even those at the earliest stages of the disease -- is popular because it has been shown to decrease the number of new HIV cases and deaths due to AIDS.

The problem, according to the study, is that such aggressive and widespread use of antiretroviral drugs would also rapidly and dramatically increase the prevalence of multiple-drug-resistant HIV (MDR).

"We're not saying that testing everybody and treating everybody is bad. All we're saying is that you should proceed with caution and closely monitor the prevalence of multi-drug-resistant HIV as you scale up the test and treat model," said lead author Neeraj Sood, associate professor at the USC Schaeffer Center for Health Policy and Economics.

Sood collaborated with Zachary Wagner, also of the USC Schaeffer Center; USC Ph.D. student Emmanuel Drabo; and Raffaele Vardavas and Amber Jaycocks of the RAND Corporation. Their study received advance online publication by Clinical Infectious Diseases on March 13.

Sood and his colleagues studied the MSM population in LA County, which accounts for 82 percent of people living with HIV/AIDS countywide. They tracked how the disease was treated from 2000 to 2009 and how the virus responded.

Using data from the Centers for Disease Control and their own data, the researchers then generated a model of how the disease would respond under a more aggressive "test and treat" policy over the next 10 years.

The model showed the prevalence of MDR jumping from 4.79 percent to 9.06 percent by 2023.

A more cautious approach, Sood suggested, would be simply to aggressively test for the disease but to avoid prescribing antiretroviral drugs to asymptomatic patients. The modeling shows that strategy still making significant gains against HIV/AIDS, without the increase in MDR HIV.

"Prior studies show a dramatic reduction in risk-taking behavior by individuals once they know their HIV-positive status," Sood said.